1. Field of the Invention
The present invention relates generally to detecting brain waves, analyzing those brain waves and applying a stimulus, or waking mechanism, when the detected brain waves are within a predetermined range, and, more particularly, to an apparatus to detect the early stages of sleep in a person applying a stimulus to wake the person up.
2. Background of the Invention and Related Art
Research shows that the human brain emits brain waves which correspond with certain activities. Using an electroencephalogram (“EEG”), researchers have observed brain wave activity in a variety of frequencies which correspond to the brain's activity state. EEGs have been used in the medical industry for monitoring brain wave activity. For example, Beta waves comprise 16-31 Hz, Alpha waves comprise 8-15 Hz, Theta waves comprise 4-7 Hz, and Delta waves comprise 0.1-3 Hz.
EEGs have been used in the medical industry for monitoring brain wave activity but have just recently entered the consumer industry. With the invention of the EEG dry sensor, a wearable device that senses brain waves was made possible. The technology has been used in devices that integrate with software to perform various functions. However, the specific application of providing a user with a constant state of alertness has never been actualized.
Researchers generally measure beta waves and alpha waves in people who are awake and alert. Beta waves are have a high frequency and low amplitude and exhibit an inconsistent pattern and correspond with day to day activities when a person is alert and awake. Beta waves are exhibited when a person is fully awake and when higher functions such as logic and critical reasoning occur.
However, as a person relaxes, the brain begins to exhibit alpha waves, which are characterized by increased amplitude and synchronicity. These brain waves correlate with peaceful meditation.
The brain emits Theta waves as a person transitions from a wakeful state in the alpha and beta ranges to a sleep state. Theta waves further decrease in frequency and further increase in amplitude. A person who emits Theta waves as they pass from a calm relaxed state into a drowsy, but still awake state and transitions to a drowsy and fully asleep state.
Finally, Delta waves are exhibited by a person who is in a deep sleep.
The body and brain have anatomical structures which control sleep. The thalamus is brain structure responsible for consciousness. The thalamus has multiple functions. It may be thought of as a kind of switchboard of information. It is generally believed to act as a relay between different subcortical areas and the cerebral cortex. In particular, every sensory system (with the exception of the olfactory system) includes a thalamic nucleus that receives sensory signals and sends them to the associated primary cortical area. For the visual system, for example, inputs from the retina are sent to the lateral geniculate nucleus of the thalamus, which in turn projects to the visual cortex in the occipital lobe. The thalamus is believed to both process sensory information as well as relay it—each of the primary sensory relay areas receives strong feedback connections from the cerebral cortex. Similarly the medial geniculate nucleus acts as a key auditory relay between the inferior colliculus of the midbrain and the primary auditory cortex, and the ventral posterior nucleus is a key somatosensory relay, which sends touch and proprioceptive information to the primary somatosensory cortex.
The thalamus also plays an important role in regulating states of sleep and wakefulness. Thalamic nuclei have strong reciprocal connections with the cerebral cortex, forming thalamo-cortico-thalamic circuits that are believed to be involved with consciousness. The thalamus plays a major role in regulating arousal, the level of awareness, and activity. Damage to the thalamus can lead to permanent coma.
While sleep is critical to maintaining health, certain activities, such as standing guard, operating a motor vehicle or even studying cannot be properly performed while asleep or even drowsy. An estimated 20% of fatalities on the road are drowsiness related. Currently, waking mechanisms that claim to sense drowsiness do so by using motion sensors. People need something to keep them awake while driving, working, monitoring, etc.